1. Field of the Invention
The present invention relates to valves and more particularly pertains to internal combustion engine valves which may be operated by means other than a conventional cam and follower arrangement.
2. Description of the Prior Art
An internal combustion engine utilizes valves for controlling a flow of an engine's intake and exhaust gases. Conventionally, a camshaft is mechanically coupled to a crankshaft of the engine by a timing belt and pulley arrangement. The camshaft has a plurality of lobes which are utilized to engage and operate respectively positioned valves.
However, since intake and exhaust valves are opened and closed by the camshaft as described above, valve timing is determined solely by a profile of the camshaft. Utilizing a conventional camshaft, it is impossible to vary the valve timing depending upon an engine's rotational speed. An engine's valve timing requirement for optimum performance and efficiency varies as a function of engine speed. Therefore, it is desirable that a valve be provided with a means for selectively operating the valve depending upon the engine's speed and other factors.
Valve actuators operable for providing variable valve timing are known in the prior art. More specifically, the devices heretofore devised and utilized for the purpose of actuating internal combustion engine valves are known to consist basically of familiar, expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements.
For example, a valve control system for an internal combustion engine is illustrated in U.S. Pat. No. 5,076,222 which utilizes an electromagnetic actuator for operating intake and exhaust valves of an engine.
U.S. Pat. No. 5,009,202 describes an electromagnetically operated valve assembly for use in an internal combustion engine that includes a ceramic valve with an increased magnetic cross section area.
In view of the prior art, it can be appreciated that there exists a continuing need for new and improved internal combustion valve actuator apparatuses which can be utilized to provide variable valve timing on an internal combustion engine. In this regard, the present invention substantially fulfills this need.